This paper presents new techniques designed to improve the performances of a BOTDR. The first one introduces a second pump to the sensor, thus doubling the Brillouin signal on the receiver. The second one uses image p...
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ISBN:
(纸本)9781509048502
This paper presents new techniques designed to improve the performances of a BOTDR. The first one introduces a second pump to the sensor, thus doubling the Brillouin signal on the receiver. The second one uses image processing with a two-dimensional Gaussian filter whose parameters are defined. The last technique explores the possibilities offered by colour codes. The benefits of each, in terms of signal-to-noise ratio, is presented by comparing measurements over a distance range of 50km with a spatial resolution of 5m. These techniques can easily be combined and the global improvement is estimated at 10dB, compared to conventional sensors.
Fluorescent polymer nanoparticles for long-term labeling and tracking of living cells with any desired color code are developed. They are built from biodegradable poly(lactic-co-glycolic acid) polymer loaded with cyan...
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Fluorescent polymer nanoparticles for long-term labeling and tracking of living cells with any desired color code are developed. They are built from biodegradable poly(lactic-co-glycolic acid) polymer loaded with cyanine dyes (DiO, DiI, and DiD) with the help of bulky fluorinated counterions, which minimize aggregation-caused quenching. At the single particle level, these particles are approximate to 20-fold brighter than quantum dots of similar color. Due to their identical 40 nm size and surface properties, these nanoparticles are endocytosed equally well by living cells. Mixing nanoparticles of three colors in different proportions generates a homogeneous RGB (red, green, and blue) barcode in cells, which is transmitted through many cell generations. Cell barcoding is validated on 7 cell lines (HeLa, KB, embryonic kidney (293T), Chinese hamster ovary, rat basophilic leucemia, U97, and D2A1), 13 color codes, and it enables simultaneous tracking of co-cultured barcoded cell populations for > 2 weeks. It is also applied to studying competition among drug-treated cell populations. This technology enabled six-color imaging in vivo for (1) tracking xenografted cancer cells and (2) monitoring morphogenesis after microinjection in zebrafish embryos. In addition to a robust method of multicolor cell labeling and tracking, this work suggests that multiple functions can be co-localized inside cells by combining structurally close nanoparticles carrying different functions.
In this paper, optical code domain reflectometer (OCDR) and optical time domain reflectometer (OTDR) are used for centralized monitoring and troubleshooting any fault occurring in the network. It combines the advantag...
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In this paper, optical code domain reflectometer (OCDR) and optical time domain reflectometer (OTDR) are used for centralized monitoring and troubleshooting any fault occurring in the network. It combines the advantages of the OTDR scheme and the optical coding scheme, which can supervise the whole long-reach passive optical network in a cost-effective manner. Network management system in the central office can initialize monitoring, locating failure, and protection process by monitoring information. The scheme can locate the faulty point precisely by OTDR after determining the failed optical fiber link by the optical coding technique. The OTDR precise positioning and protection scheme can be carried out simultaneously, thus saving recovery time. Furthermore, network performance of OCDR and OTDR, recovery time, loss, cost, bit error rate of data signal transmission are also studied. The results obtained prove the feasibility and efficiency of the proposed network, and that it can support high network capacity.
A monitoring mechanism combining the advantages of a monitoring trails scheme and an optical coding scheme is proposed;the mechanism can be used in a metro-access network. optical encoders are centrally placed in an o...
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A monitoring mechanism combining the advantages of a monitoring trails scheme and an optical coding scheme is proposed;the mechanism can be used in a metro-access network. optical encoders are centrally placed in an optical distribution network and at both sides of each remote node, which makes for much simpler installation and smaller management costs. A modified heuristic monitoring trail allocation algorithm is used for monitoring the inner links of the mesh network. The principle of the complete monitoring scheme and various fault scenes are displayed. The results show that the designed monitoring mechanism costs less and is easily scalable. This system can monitor not only the states of fiber links but also nodes in the network to alleviate the false alarm probability. It can also support high network capacity. Moreover, it can take a trade-off of the number of monitors and optical encoders.
In this paper, we propose a novel Brillouin optical time-domain analysis setup that combines simultaneous Brillouin gain/loss measurements with colour coding. This technique gives the advantage that the pump power can...
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In this paper, we propose a novel Brillouin optical time-domain analysis setup that combines simultaneous Brillouin gain/loss measurements with colour coding. This technique gives the advantage that the pump power can greatly be increased, compared to other coding schemes;thus, increasing the sensing range. A first measurement over a 200-km fiber loop is performed, with a 3-m spatial resolution and an accuracy of +/- 3 MHz (2s) at the end of the sensing fiber. In a second setup, high-power flat pump pulses are generated by applying an arbitrary waveform signal on a frequency shifter;thus, further increasing the performance of the novel Brillouin sensor. To the best of our knowledge, these are the best results obtained with a Brillouin sensor without Raman amplification.
For the first time, a colour cyclic coding (CCC) is theoretically and experimentally demonstrated for Brillouin optical time-domain analysis (BOTDA) distributed sensors. Compared to traditional intensity-modulated cyc...
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ISBN:
(纸本)9781628418392
For the first time, a colour cyclic coding (CCC) is theoretically and experimentally demonstrated for Brillouin optical time-domain analysis (BOTDA) distributed sensors. Compared to traditional intensity-modulated cyclic codes, the code presents an additional gain of root 2 while keeping the same number of sequences as for a colour coding. A comparison with a standard BOTDA sensor is realized and validates the theoretical coding gain.
Artefacts and noise degrade the decoded image of a wavefront coding infrared imaging system, which usually results in the decoded image being inferior to the in-focus infrared image of a conventional infrared imaging ...
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ISBN:
(纸本)9781510601680
Artefacts and noise degrade the decoded image of a wavefront coding infrared imaging system, which usually results in the decoded image being inferior to the in-focus infrared image of a conventional infrared imaging system. The previous letter showed that the decoded image fell behind the in-focus infrared image. For comparison, a bar target experiment at temperature of +20 degrees C and two groups of outdoor experiments at temperatures of +28 degrees C and +70 degrees C are respectively conducted. Experimental results prove that a wavefront coding infrared imaging system can achieve the decoded image being approximating to its corresponding in-focus infrared image.
We experimentally realize seamless operations with below 100-fs timing jitter in a 10-GSample/s 3-bit photonic analog-to-digital converter (ADC) with an input 2.5-GHz sinusoidal electrical signal. To address the energ...
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We experimentally realize seamless operations with below 100-fs timing jitter in a 10-GSample/s 3-bit photonic analog-to-digital converter (ADC) with an input 2.5-GHz sinusoidal electrical signal. To address the energy efficiency, it is necessary to explore some serial approaches to get most operations in a photonic ADC done before serial-to-parallel conversion to save the number of devices. To press forward with the work on subsequent operations after optical sampling in a photonic ADC, we have investigated optical quantization and coding and demonstrated their performances. The experimental results successfully demonstrated seamless operations in a photonic ADC, i.e., sampling, quantization, and coding, while keeping its parallel-configuration-free characteristics and low timing jitter below 100 fs. This demonstration could address the energy efficiency by reduction of the number of devices, including electrical ADCs for subsequent operations after optical sampling in existing high-performance photonic ADCs.
The signal-to-noise ratio and the coding gain of Brillouin optical time domain reflectometry system with APD detector are analyzed. In coding distributed optical fiber sensing system, there are a large number of multi...
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The signal-to-noise ratio and the coding gain of Brillouin optical time domain reflectometry system with APD detector are analyzed. In coding distributed optical fiber sensing system, there are a large number of multipath interferences (MPIs), which are proportional to the code length. The random shot noise caused by MPI will be generated before decoding and cannot be eliminated by decoding process. In addition, the shot noise power is proportional to the square of the code length;the thermal noise power increases linearly with the code length, then, the increase of the speed of the coding gain will be decreased with the increase of the code length. When the shot noise is much larger than the thermal noise, the coding gain will not be increased with the increase of the code length, but will maintain a constant value. This conclusion is in contradiction with the traditional conclusion. At the same time, the shot noise depends on the pulsewidth and power, but the thermal noise is independent on the pulsewidth and the power, so there exists an optimum code length for specific system.
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